Why did TikTok agree to a $400m US settlement?

TikTok agreed to pay $400 million to settle a US Department of Justice lawsuit accusing it of breaching the Children's Online Privacy Protection Act, including allowing under-13s to hold regular accounts and collecting their personal data without parental consent [1, 3]. The DOJ called it one of the largest recoveries ever secured in such a case [3]. TikTok and parent company ByteDance did not admit wrongdoing but committed to stronger age controls as part of the deal [4].